Conventionally, in various slide members, there is widely known a technique which applies a solid lubrication coating film onto the sliding surface of the slide member to thereby enhance the boundary lubrication property and dry property thereof.
Especially, in a swash cam type compressor which includes a swash plate obliquely fixed to a rotary shaft or a swash plate obliquely fixed to a rotary shaft in such a manner that the inclination angle thereof can be changed, as the rotary shaft is rotated, the swash cam increases or decreases the volume of a partitioned space existing in the interior of the compressor to thereby expand or compress a cooling medium. The above swash plate slides with respect to a seal member referred to as a shoe and seals airtight between them, whereby the cooling medium can be expanded and compressed in a given space. The peculiarity of the sliding motion of swash plate is that, since the swash plate and shoe slide with respect to each other before lubricating oil reaches the sliding surface in the initial stage of the operation of the compressor, the swash plate is slided under the dry sliding condition where the lubricating oil is not present. Also, a refrigerant in the form of gas reaches the sliding surface before new lubricating oil reaches there and cleans the lubricating oil remaining on the sliding surface. As a result of this, seizure is very easy to occur in the sliding surface.
In order to adapt the swash plate to the above-mentioned strict sliding conditions, in the case of a swash plate for a compressor as well, normally, a solid lubrication coating film is applied to the sliding surface of the swash plate before it is actually used.
In the case of the dry lubrication condition that is the severest condition of the operating conditions of a swash plate type compressor, use of solid lubricant can surely enhance the seizure resistance of the sliding surface to a certain degree; but, a film, which is obtained by joining two kinds of solid lubricant together with thermosetting resin, is unfavorably easy to wear. On the other hand, the sliding surface must also have a good sliding property for high speeds and high temperatures under the fluid lubrication condition, so that it must have a good initial running-in property.
Under the above-mentioned severe sliding condition, in case where the film application strength of the solid lubrication coating film is increased so as to enhance the wear resistance of the sliding surface, the running-in property of the sliding surface is degraded to thereby increase the sliding resistance thereof, causing the applied film to peel off, which lowers the seizure resistance of the sliding surface. On the other hand, in case where, in order to attach great importance to the running-in property, the quantity of the solid lubricant is increased or material easy to wear is used to thereby lower the strength of the film, the wear resistance and dry property of the sliding surface are degraded as well as the film is easy to wear or easy to peel off, thereby increasing the occurrence of seizure in the sliding surface; that is, the increased quantity of the solid lubricant or use of the material easy to wear puts another limit on the sliding surface in terms of seizure resistance.
In view of the above-mentioned circumstances of the prior art, it is an object of the invention to provide a slide member which is improved in the initial running-in property and also can provide an excellent sliding property even under the strict sliding conditions.
In particular, it is an object of the invention to provide a slide member with a solid lubrication coating film which can provide not only a good friction property but also excellent wear resistance under the fluid lubrication, boundary lubrication and dry lubrication conditions.